Boot-calk.



PATENTED APR. 8, 1906 C. PFEIFFERU BOOT GALK.

APPLICATION mumnovas. 1904.

WITNESSES: V 1 W0 e a tendency to slip.

IINITEU TATJEE CHRISTIAN PEEIEFER, OF

PATET IEIEICE.

NEW BRITAIN, CONNECTICUT, ASSIGNOR TO THE NORTH & IFEIEFER MANUFACTURING COMPANY, OF NEW BRITAIN,

CONNECTICUT, A CORPORATION OF CONNECTICUT.

IBOOT CALM.

Specification of Letters Patent.

Patented April 3, 1906.

Application filed November 15, 1904. Serial No. 2323437.

useful Improvements in Boot-Calks, of which the following is a description, reference being had to the accompanying drawings, and to the figures of reference marked thereon.

My invention relates to an improvement inv boot-calks of the kind used by lumbermen and log ers, and is an improvement upon the device 'Il'ustrated in the patent granted A. B. Lipscomb, August 11, 1903, No. 736,121.

As shown in said. patent, a dished stop is employed. having the threaded shank and spike, the spike for a portion of its length adjacent the stop-disk being square in crosssection, the remaining portion of its length being circular or approximately circular in cross-section and tapered to a sharp point.

In practice it has been found very difficult to get the square on the calk sufliciently'large to afford a good bearing-surface, and it is difficult in squaring the hole in the chucks to keep them uniform. Thus the chucks do not fit closely on the squared portion and there is As soon as the chucks have slipped once or twice the corners begin. to wear round and are soon useless.

It is the object of the present invention to overcome these defects and at the same time increase the strength of the dished stop.

The invention therefore consists in the matters hereinafter described and referred to in the appended claims.

The invention is'illustrated in the accompanying drawings, in which Figure 1 is a view in sectional elevation showing the manner in which the calk is applied to the boot-heel. Fig. 2 is a view in elevation of the calk and chuck.

In the drawings, 1 represents the calk, comprising the threaded shank 2, the spike 3, and the dished stop-disk 4. The latter has the integral ribs 5, extending from the shank portion of the spike 3 to the periphery of the dished stop, these ribs being adapted to fit recesses 6 in the chuck-bit brace, whereby a positive holding of the chuck to the calk is k having radiating ribs on its convex provided without any danger of slipping or wearing away of the shank and serving to strengthen the disk.

By the use of the ribs a strong and positive hold of the chuck on the body of the calk itself is possible, the spike portion thereof not being engaged at all, and by this construction the spike may be made round instead of squared and thinner in cross section than I heretofore and even when worn away materially will still be sharp enough to perform its function, whereas in the former construction as soon as the spike portion had worn down to the squared portion the spike became too' blunt for use. Furthermore, by this construction only a round hole has to be made in the center of the chuck, thus cheapening the cost thereof.

Having thus described my said invention, what I claim, and desire to secure by Letters Patent, is-

1. As a new article of manufacture, a bootcalk having a dished stop disk, a screwthreaded shank extending from the concave side thereof, and a spike extending from the convex side of the disk, said. spike tapering toward its lower end, the surface of the disk from which the spike extends having streng'thening-ribs extending from the spike toward the periphery of the disk, and adapted. also to be engaged by the chuck of an inserting-tool, the ribs terminating short of the point of the spike, substantially as described.

2. A boot-calk comprising a dished disk side, a the ribs, and a spike projecting beyond from the concave l threaded shank extending side of the disk.

3. A boot-calk comprising a dished disk having radiating ribs on its convex side, a cone shaped spi e projecting beyond the ribs, and a threaded shank extending from the. concave side of the disk.

In testimony whereof I aiIix my in presence of two witnesses.

CHRISTIAN PFEIFFER.

signature Witnesses:

J. H. KIRKHAM, C. S. STUnTnvAN'r. 

